This invention generally relates to dynamometers and specifically to a chassis dynamometer for transit vehicles.
The art of making various dynamometers has existed for decades. Continuous improvement in the construction of dynamometers for activities including brake testing, performance testing and emissions testing is evidenced by a series of issued patents including U.S. Pat. No. 5,375,461 to Suzuki, U.S. Pat. No. 4,450,728 to D'Angelo et. al., U.S. Pat. No. 4,468,955 to Yamasaki et. al., U.S. Pat. No. 4,688,419 to D'Angelo et al., U.S. Pat. No. 4,870,585 to Manzolini, U.S. Pat. No. 5,010,763 to Schneider, U.S. Pat. No. 3,277,703 to Cline, U.S. Pat. No. 3,554,023 to Geul, U.S. Pat. No. 6,257,054 to Rostkowski et. al., U.S. Pat. No. 5,193,386 to Hesse, Jr. et. al., U.S. Pat. No. 5,844,145 to D'Angelo, U.S. Pat. No. 5,450,748 to Evans et al., U.S. Pat. No. 4,483,204 to Warsaw, U.S. Pat. No. 4,899,595 to Warsaw, U.S. Pat. No. 3,289,471 to Maxwell, U.S. Pat. No. 3,490,276 to Maxwell et. al., U.S. Pat. No. 5,419,192 to Maxwell et. al., U.S. Pat. No. 4,050,299 to Maxwell, U.S. Pat. No. 3,979,950 to Maxwell and U.S. Pat. No. 3,020,753 to Maxwell.
The use of chassis dynamometers for measuring various variables in automotive performance is widely known in the industry. A chassis dynamometer generally includes a frame, at least one set of rollers supported on a frame and a dynamometer attached to the rollers for the purpose of road load stimulation.
For brake testing, general motoring and driving of chassis dynamometer rollers, much less power is required than is necessary for load testing to measure the vehicle power. Frequently, machines use a motor or electric dynamometer that is capable of both functions, i.e. motoring and absorbing power with the chassis dynamometer. However, with the advent of higher horsepower vehicles, it has become necessary to have machines that require greatly oversized motors or electric dynamometers to provide full vehicle power absorption while still providing the lesser power required for driving the rollers. An additional disadvantage of using a large motor or electric dynamometer is the necessity to dissipate heat generated through a resistive load bank or to regenerate the absorbed power as electrical power. Both these functionalities add undesirable complexity and additional cost to the machine.
Accordingly, the need exists for a motoring chassis dynamometer that is very economic in construction. The motoring chassis dynamometer must be modularly built such that the machine may be easily assembled transported and installed as modules. Similarly, if any repair, maintenance or adjustment is required on the chassis dynamometer, the chassis dynamometer may be capable of easy modular disassembly, repair, maintenance and adjustment. Also, the need exists for a chassis dynamometer to provide test performance surpassing the current and anticipated vehicle capability so that tests of vehicle performance, such as brake testing, transmission testing and full engine power testing for higher horsepower vehicles, can be performed without greatly over-sizing the motor or electric dynamometer. The need also exists to offer alternatives to the currently existing dynamometers to provide the same or greater performance by using a reduced size motor and appropriately sized dynamometer. Finally the need exists to construct chassis dynamometers to allow for testing of both low horsepower and high horsepower vehicles by decreasing construction and equipment cost.